1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method thereof, and more particularly, to a semiconductor device capable of reducing the electrical leakage of a semiconductor device caused when a contact hole is misaligned and a manufacturing method thereof.
2. Discussion of Related Art
Recently, in conjunction with the development of ever higher density semiconductor devices which provide greater functionality, various information devices in which semiconductor devices are installed, such as computers, mobile phones, personal digital assistants, and the like, have grown ever more popular. Semiconductors installed in these information devices are required to have a high operating speed and a great deal of storage capacity. In order to satisfy these requirements, semiconductor device manufacturing technology is developing to improve integration, reliability, and response speed.
Moreover, as the degree of integration increases and the size of devices decrease, the distances between conductive layers forming the semiconductor devices gradually decrease. At its most basic level, the semiconductor device includes a plurality of conductive layers formed on a substrate and a plurality of insulating layers formed between the conductive layers. In order to form a semiconductor device with higher density in a more accurate way, a reduction in the thickness of the conductive layer or a reduction in the distance between the conductive layers (e.g., the thickness of the insulating layers) is typically proposed. However, by reducing the thickness of the conductive layers or the distance between the conductive layers, formation a contact hole electrically connecting the conductive layers to each other becomes more difficult.
Hereinafter, the conventional formation of a contact hole will be described with reference to the accompanying drawings.
FIG. 1A is a schematic plan view illustrating a conventional semiconductor device formed with a contact hole. FIG 1B is an enlarged side view taken along line I-I′ in FIG. 1A. As shown in FIG. 1A and FIG 1B, a semiconductor device 100 includes a plurality of conductive layers 110, 120, and 130 formed on a substrate (not shown), a plurality of insulating layers 115 and 125 formed between the conductive layers 110 and 120 and between the conductive layers 120 and 130, respectively, and a contact hole 140 for electrically connecting a pair of conductive layers among the conductive layers 110, 120, and 130.
As shown in FIG. 1A, on top of the substrate, a “line-shaped” first conductive layer 110 is formed. When discussing “line-shaped” or “minus-shaped” conductive layers throughout the specification, the conductive layers may be a line segment or a displayed portion of a longer line, and the length, width, angle, and shape of the conductive layers are not limited to the sizes, angles, and shapes displayed by the drawings. Moreover, line-shaped and minus-shaped conductive layers may be shaped similarly, and the nomenclature is adopted only to identify the approximate orientation of the conductive layers in the drawings. Although not depicted in the drawings, a buffer layer is generally formed between the substrate and the first conductive layer 110, and can act as an insulating layer between the substrate and the first conductive layer 110. On top of the first conductive layer 110, a first insulating layer 115 is formed to cover at least the first conductive layer 110. On top of the first insulating layer 115, a minus-shaped second conductive layer 120 overlapped with at least some portion of the first conductive layer 110, is formed. On top of the second conductive layer 120, a second insulating layer 125 is formed to cover at least some of the second conductive layer 120. On top of the second insulating layer 125, a line-shaped third conductive layer 130 is formed at least partially overlapping the first conductive layer 110 and the second conductive layer 120. Within the second insulating layer 125, the contact hole 140 is formed to electrically connect the second conductive layer 120 to the third conductive layer 130. Thus, the contact hole 140 electrically connects the two adjacent conductive layers to each other.
However, when a plurality of conductive layers and insulating layers between adjacent conductive layers is built using either a reduction in thickness of the conductive layers or a reduction in distance between the conductive layers, the problem shown in FIGS. 2A and 2B may occur. FIG. 2A is a top schematic view of a contact hole in an unconventional formation position, and FIG. 2B is an enlarged side view taken along line II-II′ in FIG. 2A. As shown in the drawings, contact hole 140 is electrically connected to conductive layers 120 and 130 to which the contact hole 140 must be electrically connected, and contact hole 140 is also electrically connected to conductive layer 110 to which contact hole 140 must not be electrically connected. Moreover, as shown in FIGS. 2A and 2B, when the formation position of the contact hole 140 is such that it is electrically connected to the conductive layer 110 to which the contact hole 140 must not be electrically connected, electric leakage may occur.